Propeller for watercraft

ABSTRACT

A propeller includes a blade device and a driving device. The blade device includes a ring-shaped base with an inner base surface and defining a base axis, and a plurality of curved blades, each of which extends from the inner base surface of the ring-shaped base toward the base axis. The blades are angularly spaced apart from each other relative to the base axis, and cooperate to define a flow space located in the ring-shaped base at the base axis. The driving device drives the blade device to rotate about the base axis.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The invention relates to a propeller, more particularly to a watercraftpropeller.

2. Description of the Related Art

Referring to FIGS. 1 and 2, conventional propellers 1 are mounted on twosides of a watercraft 9 to enable forward advancing movement of thelatter on a body of water. Each propeller 1 includes a hub 11, aplurality of blades 12 extending from the hub 11 and angularly spacedapart from each other, and a motor 13 having a propeller shaft connectedto the hub 11. When the hub 11 is driven by the motor 13 to rotate, theblades 12 rotate accordingly to enable water flow in a front-to-reardirection.

In the aforesaid propeller 1, the hub 11 occupies a central regionsurrounded by the blades 12. Hence, water is unable to flow through thecentral region and only flows through clearances among the blades 12.There is thus a need to increase the volume of water that can be movedby the propeller 1 to promote propelling efficiency of the same.

SUMMARY OF THE INVENTION

Therefore, the object of the present invention is to provide a propellerthat can overcome the above drawback associated with the prior art.

Accordingly, a propeller of the present invention comprises a bladedevice and a driving device. The blade device includes a ring-shapedbase with an inner base surface and defining a base axis, and aplurality of curved blades, each of which extends from the inner basesurface of the ring-shaped base toward the base axis. The blades areangularly spaced apart from each other relative to the base axis, andcooperate to define a flow space located in the ring-shaped base at thebase axis. The driving device drives the blade device to rotate aboutthe base axis.

BRIEF DESCRIPTION OF THE DRAWINGS

Other features and advantages of the present invention will becomeapparent in the following detailed description of the preferredembodiment with reference to the accompanying drawings, of which:

FIG. 1 is a schematic view of a watercraft mounted with a pair ofconventional propellers;

FIG. 2 is a schematic view of the conventional propeller;

FIG. 3 is an exploded perspective view of the preferred embodiment of apropeller according to the present invention;

FIG. 4 is an exploded schematic sectional view of the preferredembodiment;

FIG. 5 is a fragmentary schematic view of the preferred embodiment forillustrating engagement between a blade device and a driving device;

FIG. 6 is a fragmentary schematic view of the blade device of thepreferred embodiment for illustrating connection of blades to an innerbase surface of a ring-shape base of the blade device;

FIG. 7 is a partly sectional, schematic side view of the preferredembodiment; and

FIGS. 8 and 9 are schematic views to illustrate the preferred embodimentwhen mounted on a watercraft.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT

Referring to FIGS. 3 to 7, the preferred embodiment of a propelleraccording to the present invention is shown to comprise a retaining unit2, a blade device 3, and a driving device 4.

The retaining unit 2 includes an annular seat 21 that is formed with anannular base retaining space 22. The seat 21 includes first and secondseat parts 211 that are connected to each other and that cooperate todefine the base retaining space 22.

The blade device 3 includes a ring-shaped base 31 retained rotatably inthe base retaining space 22 and defining a base axis (L), and aplurality of curved blades 32. The ring-shaped base 31 has an inner basesurface 311 surrounding the base axis (L), and an outer base surfaceopposite to the inner base surface in radial directions relative to thebase axis (L) and formed with gear teeth 312. The ring-shaped base 31further has first and second ends opposite to each other along the baseaxis (L). Each of the first and second ends of the ring-shaped base 31is formed with an annular groove 313. The blades 32 extend from theinner base surface 311 of the ring-shaped base 31 toward the base axis(L), are angularly spaced apart from each other relative to the baseaxis (L), and cooperate to define a flow space 33 located in thering-shaped base 31 at the base axis (L). Each of the blades 32 is inthe shape of a bent curved fan, and has a curved edge portion 321inclined relative to the base axis (L) and connected to the inner basesurface 311 of the ring-shaped base 31 (see FIG. 6), and a cornerportion 322 with a tip that extends into the flow space 33.

The retaining unit 2 further includes bearing components 23 disposed inthe base retaining space 22 between the seat parts 211 of the seat 21and the opposite ends of the ring-shaped base 31. While the bearingcomponents 23 in this embodiment include a plurality of ball bearings231 received in the annular grooves 313, the actual configuration of thebearing components should not be limited thereto in practice.

The seat 21 is formed with a cutout 210 (see FIG. 5) to expose some ofthe gear teeth 312 of the ring-shaped base 31. The driving device 4includes a drive gear 41 that meshes with the exposed gear teeth 312 ofthe ring-shaped base 31, and a drive member 42, such as a drive motor,for driving rotation of the drive gear 41. The driving device 4 drivesthe blade device 3 to rotate about the base axis (L).

During operation, the drive member 42 rotates the drive gear 41 so as torotate the ring-shaped base 31 together with the blades 32 about thebase axis (L). As a result, water can be moved to flow throughclearances among the blades 32 in a front-to-rear direction, as well asthrough the flow space 33 defined by the blades 32 and located in thering-shaped base 31 at the base axis (L). Hence, the volume of waterthat can be moved without obstruction by the propeller of this inventionis increased to promote propelling efficiency.

Referring to FIGS. 8 and 9, the propeller of this invention is appliedto a watercraft 5. The watercraft 5 has a bottom part formed with a flowduct 51 that extends in a front-to-rear direction. The propeller ismounted on the bottom part of the watercraft 5 such that the bladedevice 3 is disposed in the flow duct 51. When the driving device 4drives rotation of the blade device 3, water is able to flow through theflow duct 51 in the front-to-rear direction to enable forward advancingmovement of the watercraft 5. In practice, the propeller may be mountedon lateral sides of a watercraft to achieve the same propelling effect.

It should be noted herein that the propeller of this invention may bemodified such that a single drive device 4 is employed to drive rotationof more than one blade device 3 so as to further promote the propellingefficiency.

While the present invention has been described in connection with whatis considered the most practical and preferred embodiment, it isunderstood that this invention is not limited to the disclosedembodiment but is intended to cover various arrangements included withinthe spirit and scope of the broadest interpretation so as to encompassall such modifications and equivalent arrangements.

1. A propeller comprising: a blade device including a ring-shaped basewith an inner base surface and defining a base axis, and a plurality ofcurved blades, each of which extends from said inner base surface ofsaid ring-shaped base toward said base axis, said blades being angularlyspaced apart from each other relative to said base axis and cooperatingto define a flow space located in said ring-shaped base at said baseaxis; and a driving device for driving said blade device to rotate aboutsaid base axis.
 2. The propeller as claimed in claim 1, wherein saidring-shaped base further has an outer base surface formed with gearteeth, said driving device including a drive gear meshing with said gearteeth, and a drive member for driving rotation of said drive gear. 3.The propeller as claimed in claim 1, further comprising a retaining unitthat includes an annular seat formed with an annular base retainingspace that surrounds said base axis and that has said ring-shaped baseretained rotatably therein.
 4. The propeller as claimed in claim 3,wherein said retaining unit further includes bearing components disposedin said base retaining space between said annular seat and saidring-shaped base.
 5. The propeller as claimed in claim 4, wherein saidring-shaped base further has first and second ends opposite to eachother along said base axis, each of said first and second ends of saidring-shaped base being formed with an annular groove, said bearingcomponents including a plurality of ball bearings received in saidannular grooves in said first and second ends of said ring-shaped base.6. The propeller as claimed in claim 1, wherein each of said blades hasa curved edge portion inclined relative to said base axis and connectedto said inner base surface of said ring-shaped base, and a cornerportion with a tip that extends into said flow space.